Nonreciprocal entanglement via Barnett effect in a hybrid quadpartite system

Abstract We present a theoretical scheme for nonreciprocal entanglement in a quadpartite system via the Barnett effect. Our quadpartite system is based on a microwave cavity, simultaneously coupled with phonon, an LC circuit, and magnon via radiation pressure, adjustable capacitance of the LC circuit, and Kittel magnetostatics, respectively. By changing the magnetic field’s direction, the Barnett effect produces a Barnett frequency shift that may be efficiently controlled to be either negative or positive. By controlling system parameters, we show that, by employing a bidirectional contrast ratio, multipartite entanglements can be non-reciprocally enhanced via the Barnett shift. In addition, Barnett’s shift also affects the robustness of these entanglements against the bath temperature. Such a system with a variety of control mechanisms might find a range of applications in quantum technologies, computation, and information processing.